1. Technical Field
The present invention relates to a dielectric resonant antenna using a matching substrate.
2. Description of the Related Art
As a transmitting/receiving system according to the related art, products configured by assembling separate parts have been mainly used. However, recent study on system on package (SOP) products that makes the transmitting/receiving system using a millimeter wave band into a single package has been conducted. Some products of them have been commercialized.
A technology for providing the single package product has been developed, together with a multi-layer substrate process technology that stacks a dielectric substrate such as low temperature co-fired ceramic (LTCC) and liquid crystal polymer (LCP).
The aforementioned multi-layer substrate package is manufactured in a single process by integrating ICs, active devices, as well as building passive devices in the package. As a result, inductance component can be reduced due to the reduction in the number of conducting wires, inter-device coupling loss can be reduced, and production costs can be saved.
However, in the case of the LTCC process, shrinkage occurs by about 15% in x and y directions, that is, a substrate plane direction during the firing process, and thus, process errors occur, which reduces the reliability of the products.
In the multi-layer structure environment such as the LTCC process and the LCP process, a patch antenna having planar characteristics has been mainly used. However, this is unsuitable because the bandwidth of the patch antenna generally narrows by 5%.
In order to expand the bandwidth in the patch antenna, a patch antenna that generates multi-resonance by adding a parasitic patch on the same plane as the patch antenna serving as a main radiator or a stack-patch antenna that induces multi-resonance by stacking two or more patch antennas, and so on has been used.
It has been known that the related art can obtain a bandwidth of about 10% by using the multi-resonance technology.
However, when using the multi-resonance technology, a radiation pattern of an antenna may be different for each resonance frequency and the antenna characteristics due to the process errors may change to be larger than the single resonator antenna.
Therefore, in order to increase the efficiency of the antenna and secure a wider bandwidth of the antenna, and so on, a dielectric resonator antenna (DRA) has been used in the past.
It has been known that the existing dielectric resonator antenna has excellent characteristics in regards to the bandwidth and efficiency, compared with the existing multi-resonance patch antenna.
Although the existing dielectric resonator antenna is often used in order to improve the drawback of the existing patch antenna, it requires a separate dielectric resonator disposed outside of the substrate. Therefore, it is more difficult to manufacture the dielectric resonator antenna than the patch antenna having the stacked structure formed by the single process.
In addition, the dielectric resonator antenna can generate multi-resonance corresponding to the increase in the size of the dielectric resonator (for example, the length in a direction having no effect on the resonance frequency) to secure a wider bandwidth, but is disadvantageous in that the radiation pattern of the dielectric resonator antenna becomes skewed within the bandwidth.
Further, the dielectric resonator antenna generates a large reflected wave at an interface surface between a high-K multi-layer substrate including the dielectric resonator antenna and air which has a bandwidth narrower than the non-resonator antenna.